A continuation of the comprehensie study of human and canine prostatic hyperplasia (BPH) will be conducted to further our understanding of the etiology, prevention and treatment of this most prevalent disease. Animal models will be evaluated to ascertain their advantages and limitations as predictive systems for the study of the human disease. The etiological role of steroids will be evaluated in the induction and onset of canine BPH. Information will be obtained on the effects of hormones on specific types of cells within the prostate and upon their ability to induce specific steroid metabolism profiles which are associated with the spontaneous disease. A detailed study of the endocrinological events occurring within the prostate cells, such as the induction of specific steroid receptor proteins, will be determined. Age related changes will be evaluated in both the testes and the prostates of the dog, hamster, rat and man. Age-matched studies are designed to elucidate the presence of specific factors accompanying the onset and development of BPH in the dog and man. Protocols are designed to evaluate factors that prevent development of BPH in the dog and assess various therapeutic modalities in treating and controlling the established disease. The important finding related to endocrinological events associated with the pathology of canine BPH will be studied in a comparative manner in other animal models, including the spontaneous development of hamster BPH, and to determine if it is possible to produce an experimentally induced BPH in the baboons. In studies previously supported by the grant, we have developed specific physiological changes associated with both spontaneous and induced BPH in the dog. It is now proposed to further expand and elucidate these findings as well as to correlate them in other systems.